A semiconductor substrate for a light-emitting diode, heterojunction transistor or the like. Included is a buffer region of an aluminum-containing nitride or the like grown epitaxially on a baseplate of silicon or a silicon compound. A dislocation-refracting region of an indium-containing nitride is grown epitaxially on the buffer region in order to provide a major surface having a multiplicity of protuberances of pyramidal shape capable of refracting the dislocations created in the buffer region. A leveling region of a nitride, not containing indium, is formed on the major surface of the dislocation refracting region in order to provide a major surface of greater levelness than the transition refracting region. The leveling region is reduced in dislocation density owing to the interposition of the dislocation refracting region between buffer region and leveling region.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method of fabricating a semiconductor substrate for a com-pound semiconductor device, comprising: (a) providing a baseplate of a substance that permits epitaxial growth of compound semiconductors thereon; (b) creating a buffer region by causing a first compound semiconductor to grow epitaxially on the baseplate, the buffer region possibly containing dislocations; (c) creating a dislocation refracting region on a major surface of the buffer region by causing a second compound semiconductor, different from the first compound semiconductor, to grow epitaxially on the major surface of the buffer region, the dislocation refracting region having a major surface with a multiplicity of protuberances capable of refracting extensions of the dislocations from the buffer region; and (d) creating a leveling region on the major surface of the dislocation refracting region by causing a third compound semiconductor, different from the second compound semiconductor, to grow epitaxially on the major surface of the dislocation refracting region, the leveling region having a major surface of greater levelness than the major surface of the dislocation refracting region; (e) whereby the leveling region is less in dislocation density than the buffer region and the dislocation refracting region as the dislocations created in the buffer region are refracted away from the leveling region by the protuberances on the major surface of the dislocation refracting region.
2. The method of claim 1 wherein the second compound semi-conductor for the dislocation refracting region is an indium-containing nitride.
3. The method of claim 1 wherein the dislocation refracting region is formed by: (a) creating a first layer on the major surface of the buffer region by causing a first nitride to grow epitaxially thereon, the first nitride containing indium in a first proportion; (b) creating a second layer on the first layer by causing a second nitride to grow epitaxially thereon, the second nitride containing indium in a second proportion that is greater than the first proportion; and (c) repeating the steps (a) and (b) a prescribed number of times.
Cooperative Patent Classification codes for this invention. Click any code to explore related patents in that topic.
March 30, 2004
May 10, 2005
Browse 5M+ US patents with plain-English claim translations and AI-generated analysis.